1. Field of the Invention
The present invention relates to a method of treating a neurological condition in a mammal by administering at least one hematopoietic growth factor.
2. Discussion of the Related Art
Growth factors are proteins that are essentially involved in regulating survival, proliferation, maturation, and outgrowth of developing neuronal cells. For example, the expression of a large number of growth factors increases in response to various brain insults. Many factors display endogenous neuroprotective and neurotrophic effects (see Arvidsson A et al., Neuroscience 2001; 106:27-41; Larsson E, et al., J Cereb Blood Flow Metab 1999; 19:1220-8; Mattson M P, et al., J Neurotrauma 1994; 11:3-33; Semkova I, et al., Brain Res Brain Res Rev 1999; 30:176-88). These effects were also reported after exogenous administration in vitro and in vivo after brain trauma and stroke (see Semkova I., et al., Brain Res. Rev. 1999; 30:176-88; Fisher M, et al., J. Cereb. Blood Flow Metab. 1995; 15:953-9; Schäbitz W R, et al., Stroke 2001; 32:1226-33; Schäbitz W R, et al., Stroke 2000; 31:2212-7). After binding to high-affinity membrane receptors the effects of growth factors are mediated by a cascade of intracellular signal-transduction events (Kernie S G, et al., Arch Neurol 2000; 57:654-7), which induces cells to grow and differentiate; or provides trophic support for cell survival.
Granulocyte-colony stimulating factor (GCSF), a 20 kDa protein, together with tumor necrosis factor-α (TNF-α) and the interleukins is a member of the cytokine family of growth factors. GCSF is the major growth factor involved in the production of neutrophilic granulocytes.
GCSF exerts its function via the activation of a membrane receptor (GCSF receptor) that belongs to the super-family of hematopoietin receptors, also being referred to as class I cytokine receptors (de Koning and Touw, Curr. Opin. Hematol., 1996, 3, 180-4).
A number of receptors for lymphokines, hematopoietic growth factors, and growth hormone-related molecules have been found to share a common binding domain. These receptors are referred to as hematopoietin receptors and the corresponding ligands as hematopoietins. Further, hematopoietins have been subdivided into two major structural groups: Large/long and small/short hematopoietins. One subset of individual receptor chains that are part of receptor complexes for large hematopoietins contain common structural elements in their extracellular parts: an immunoglobin-like domain, a hematopoietin-receptor domain, and 3 fibronectin type-III domains (2 in the leptin receptor). This subgroup was designated the “gp130 family of receptors” (Mosley, et al. J. Biol. Chem. 1996, 271, 32635-43) and include Leptin receptor (LPTR), Granulocyte colony stimulating factor receptor (GCSFR), Interleukin-6/-11/LIF/OSM/CNTF common beta chain (GP130), Leukemia inhibiting factor receptor (LIFR), Oncostatin-M receptor beta chain (OSMR), interleukin-12 receptor beta-1 chain (IL12RB1), Interleukin-12 receptor beta-2 chain (IL12RB2). These receptor chains homodimerize (GCSFR, GP130, LPTR) or heterodimerize (GP130 with LIFR or OSMR, IL12RB1 with IL12RB2) upon binding the cognate cytokine. In addition, a prosite consensus pattern is characteristic of this receptor family, which is:
N-x(4)-S-x(28,35)-[LVIM]-x-W-x(0,3)-P-x(5,9)-[YF]-x(1,2)-[VILM]-x-W (SEQ ID NO:1)
GCSF stimulates proliferation, survival, and maturation of cells committed to the neutrophilic granulocyte lineage through binding to the specific GCSF receptor (GCSFR) (see Hartung T., et al., Curr. Opin. Hematol. 1998; 5:221-5). GCSFR mediated signaling activates the family of Signal Transducer and Activator of Transcription (STAT) proteins which translocate to the nucleus and regulate transcription (Darnell J E Jr., Science 1997; 277:1630-5). GCSF is typically used for the treatment of different kinds of neutropenia in humans. It is one of the few growth factors approved for clinical use. In particular, it is used to reduce chemotherapy (CT)-induced cytopenia (Viens et al., J. of Clin. Oncology, Vol. 20, No. 1, 2002:24-36). GCSF has also been implicated for therapeutic use in infectious diseases as potential adjunctive agent (Hübel et al., J. of Infectious Diseases, Vol. 185:1490-501, 2002). GCSF has reportedly been crystallized to some extent (EP 344 796), and the overall structure of GCSF has been surmised, but only on a gross level (Bazan, Immunology Today 11:350-354 (1990); Parry, et al. J. Molecular Recognition 8:107-110 (1988)).
In recent years a number of growth factors such as bFGF and pharmaceutically promising substances such as thrombocyte adhesion blockers like anti-GP IIb/IIa and Abcizimab have been tested for neuroprotective efficacy in clinical studies. Unfortunately, none of these prevailed to provide neuroprotective efficacy. In particular, NMDA antagonists, free radical scavengers and glutamate antagonists failed or demonstrated severe side-effects. The list of substances such as anti-ICAM or inhibitors of the glutamate-mediated NO-synthetase that have failed growing (De Keyser, et al. (1999), Trends Neurosci, 22, 535-40).
Most studies on cerebral ischemia and testing of pharmacological substances in vivo have only been concerned with the immediate effects of the drug or paradigm under investigation (i.e. infarct size 24 h after induction of the stroke). However, a more valid parameter of true efficacy of a particular substance is the long-term effect on functional recovery, which is also reflected in human stroke studies, where clinical scales (e.g., Scandinavian stroke scale, NIH scale, Barthel index) also reflect the ability to perform daily life activities. Recovery in the first few days after focal lesions may be due to resolution of edema or reperfusion of the ischemic penumbra. Much of the functional recovery after the acute phase is likely due to brain plasticity, with adjacent cortical areas of the brain taking over functions previously performed by the damaged regions (Chen R, Cohen L G, Hallett M. Neuroscience 2002; 111(4):761-73). The two main mechanisms proposed to explain reorganization are unmasking of previously present but functionally inactive connections and growth of new connections such as collateral sprouting (Chen R, Cohen L G, Hallett M. 2002 Neuroscience 2002; 111(4):761-73). Short term plastic changes are mediated by removing inhibition to excitatory synapses, which is likely due to reduced GABAergic inhibition (Kaas J H. Annu Rev Neurosci. 1991; 14:137-67; Jones E G. Cereb Cortex. 1993 September-October; 3(5): 361-72.). Plasticity changes that occur over a longer time involve mechanisms in addition to the unmasking of latent synapses such as long-term potentiation (LTP), which requires NMDA receptor activation and increased intracellular calcium concentration (Hess and Donoghue, J Neurophysiol. 1994 71(6): 2543-7). Long term changes also involve axonal regeneration and sprouting with alterations in synapse shape, number, size and type (Kaas J H. Annu Rev Neurosci. 1991; 14: 137-67., 3:).
Stroke is the third-leading cause of death, and the main cause of disability in the western world. It presents a large socioeconomic burden. The etiology can be either ischemic (in the majority of cases) or hemorraghic. The cause of ischemic stroke is often embolic, or thrombotic. So far, there is no effective treatment for the majority of stroke patients. The only clinically proven drugs so far are tissue plasminogen activator (TPA) and Aspirin. After massive cell death in the immediate infarct core due to lack of glucose and oxygen, the infarct area expands for days, owing to secondary mechanisms such as glutamate excitotoxicity, apoptotic mechanisms, and generation of free radicals.
Amyotrophic lateral sclerosis (ALS; Lou-Gehrig's disease; Charcot's disease) is a neurodegenerative disorder with an annual incidence of 0.4 to 1.76 per 100.000 population (Adams et al., Principles of Neurology, 6th ed., New York, pp 1090-1095). It is the most common form of motor neuron disease with typical manifestations of generalized fasciculations, progressive atrophy and weakness of the skeletal muscles, spasticity and pyramidal tract signs, dysarthria, dysphagia, and dyspnea. The pathology consists principally in loss of nerve cells in the anterior horn of the spinal cord and motor nuclei of the lower brainstem, but can also include the first order motor neurons in the cortex. Pathogenesis of this devastating disease is still largely unknown, although the role of superoxide-dismutase (SOD1) mutants in familial cases has been worked out quite well, which invokes an oxidative stress hypothesis. So far, more than 90 mutations in the SOD1 protein have been described, that can cause ALS (Cleveland and Rothstein (2001), Nat Rev Neurosci, 2, 806-19). Also, a role for neurofilaments in this disease was shown. Excitotoxicity, a mechanism evoked by an excess glutamate stimulation is also an important factor, exemplified by the beneficial role of Riluzole in human patients. Most convincingly shown in the SOD1 mutants, activation of caspases and apoptosis seems to be the common final pathway in ALS (Ishigaki et al. (2002), J Neurochem, 82, 576-84., Li, et al. (2000), Science, 288, 335-9). Therefore, it seems that ALS also falls into the same general pathogenetic pattern that is also operative in other neurodegenerative diseases and stroke, e.g. glutamate involvement, oxidative stress, and programmed cell death.
Parkinson's disease is the most frequent movement disorder, with approximately 1 million patients in North America; about 1 percent of the population over the age of 65 years is affected. The core symptoms of the disease are rigor, tremor and akinesia (Adams et al., Principles of Neurology, 6th ed., New York, pp 1090-1095). The etiology of Parkinson's disease is not known. Nevertheless, a significant body of biochemical data from human brain autopsy studies and from animal models points to an ongoing process of oxidative stress in the substantia nigra, which could initiate dopaminergic neurodegeneration. Oxidative stress, as induced by the neurotoxins 6-hydroxydopamine and MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), has been used in animal models to investigate the process of neurodegeneration. Although a symptomatic therapy exists (e.g. L-DOPA plus a decarboxylase inhibitor; bromocriptine, pergolide as dopamin agonists; and anticholinergic agents such as trihexyphenidyl (artane)), there is a clear need for a causative therapy, e.g. a neuroprotective therapy, that really halts the disease progress. These animal models have been used to test the efficacy of radical scavengers, iron chelators, dopamine agonists, nitric oxide synthase inhibitors and certain calcium channel antagonists. Apoptotic mechanisms are clearly operative in the animal models as well as in the patient (Mochizuki, et al. (2001), Proc. Natl. Acad. Sci. USA, 98, 10918-23, Xu et al. (2002), Nat. Med., 8, 600-6, Viswanath, et al. (2001), J. Neurosci., 21, 9519-28, Hartmann, et al. (2002), Neurology, 58, 308-10). This pathophysiology with involvement of oxidative stress and apoptosis also places Parkinson's disease amongst the other neurodegenerative disorders and stroke.
Cerebral ischemia may result from a variety of causes that impair cerebral blood flow (CBF) and lead to deprivation of both oxygen and glucose. Traumatic brain injury (TBI), on the other hand, involves a primary mechanical impact that usually causes skull fracture and abruptly disrupts the brain parenchyma with shearing and tearing of blood vessels and brain tissue. This, in turn, triggers a cascade of events characterized by activation of molecular and cellular responses that lead to secondary injury. The evolution of such secondary damage is an active process in which many biochemical pathways are involved (Leker and Shohami (2002), Brain Res. Rev., 39, 55-73). Many similarities between the harmful pathways that lead to secondary cellular death in the penumbral ischemic zone and in the area exposed to secondary post-traumatic injury have been identified (e.g. excitotoxity by excess glutamate release, nitric oxide, reactive oxygen species, inflammation, and apoptosis (Leker and Shohami (2002), Brain Res. Rev., 39, 55-73)). In addition, early ischemic episodes are reported to occur after traumatic brain injury, adding a component of ischemia to the primary mechanical damage.
Cardiovascular disease is the major cause of death in western industrialized nations. In the United States, there are approximately 1 million deaths each year with nearly 50% of them being sudden and occurring outside the hospital (Zheng, et al. (2001), Circulation, 104, 2158-63). Cardio-pulmonary resuscitation (CPR) is attempted in 40-90 of 100,000 inhabitants annually, and restoration of spontaneous circulation (ROSC) is achieved in 25-50% of these patients. However, the hospital discharge rate following successful ROSC is only 2-10% (Bottiger, et al. (1999), Heart, 82, 674-9). Therefore, the vast majority of the cardiac arrest victims annually in the United States is not treated successfully. The major reason for the low survival rates after successful CPR, i.e., for postarrest in-hospital mortality, is persistent brain damage. Brain damage following cardiocirculatory arrest is related both to the short period of tolerance to hypoxic stress and to specific reperfusion disorders (Safar (1986), Circulation, 74, UV138-53, Hossmann (1993), Resuscitation, 26, 225-35). Initially, a higher number of patients can be stabilized hemodynamically after cardiocirculatory arrest; many of them, however, die due to central nervous system injury. The personal, social, and economic consequences of brain damage following cardiac arrest are devastating. One of the most important issues in cardiac arrest and resuscitation (“whole body ischemia and reperfusion”) research, therefore, is cerebral resuscitation and postarrest cerebral damage (Safar (1986), Circulation, 74, IV138-53, Safar, et al. (2002), Crit Care Med, 30, p. 140-4). Presently, it is not possible to decrease the primary damage to neurons that is caused by hypoxia during cardiac arrest by any post-arrest therapeutic measures. Major pathophysiological issues include hypoxia and subsequent necrosis, reperfusion injury with free radical formation and cellular calcium influx, release of excitatory amino acids, cerebral microcirculatory reperfusion disorders, and programmed neuronal death or apoptosis (Safar (1986), Circulation, 74, IV138-53, Safar et al. (2002), Crit Care Med, 30, 140-4).
Several clinical trials have attempted to improve neurological outcome after cardiac arrest without success. The therapeutic use of barbiturates (to enhance neuroprotection) or the use of calcium channel blockers (to reduce ischemia reperfusion damage) was tested (Group (1986), Am. J. Emerg. Med., 4, 72-86, Group (1986), N. Engl. J. Med., 314, 397-403, Group (1991), Control Clin. Trials, 12, 525-45, Group (1991), N. Engl. J. Med., 324, 1225-31). To date no specific post-arrest treatment options are available to improve neurological outcome following cardiocirculatory arrest in the clinical setting (with the possible exception of mild hypothermia and thrombolysis where the results of large, randomized, and controlled clinical trials are eagerly awaited (Safar et al (2002), Crit. Care Med., 30, 140-4)). Therefore, an innovative therapy to improve neurological outcome after cardiac arrest is crucial.
Multiple sclerosis is the prototype inflammatory autoimmune disorder of the central nervous system and, with a lifetime risk of one in 400, potentially the most common cause of neurological disability in young adults. Worldwide, there are about 2-5 million patients suffering from this disease (Compston and Coles (2002), Lancet, 359, 1221-31.). As with all complex traits, the disorder results from interplay between as yet unidentified environmental factors and susceptibility genes. Together, these factors trigger a cascade of events, involving engagement of the immune system, acute inflammatory injury of axons and glia, recovery of function and structural repair, post-inflammatory gliosis, and neurodegeneration. The sequential involvement of these processes underlies the clinical course characterized by episodes with recovery, episodes leaving persistent deficits, and secondary progression. The aim of treatment is to reduce the frequency, and limit the lasting effects of relapses, relieve symptoms, prevent disability arising from disease progression, and promote tissue repair.
Depression is a common mental disorder characterized by sadness, loss of interest in activities and by decreased energy. Depression is differentiated from normal mood changes by the extent of its severity, the symptoms and the duration of the disorder. Suicide remains one of the common and often unavoidable outcomes of depression. If depressive episodes alternate with exaggerated elation or irritability they are known as bipolar disorder. Depressive disorders and schizophrenia are responsible for 60% of all suicides. The causes of depression can vary. Psychosocial factors, such as adverse living conditions, can influence the onset and persistence of depressive episodes. Genetic and biological factors can also play a part.
An estimated 121 million people currently suffer from depression. Depression is the leading cause of disability as measured by YLDs (Years Lived with Disability) and the 4th leading contributor to the global burden of disease (DALYs=Disability Adjusted Life Years; The sum of years of potential life lost due to premature mortality and the years of productive life lost due to disability) in 2000. An estimated 5.8% of men and 9.5% of women will experience a depressive episode in any given year. By the year 2020, depression is projected to reach second place of the ranking of DALYs calculated for all ages, both sexes. In the developed regions, depression will then be the highest ranking cause of burden of disease.
Today the first-line treatment for most people with depression consists of antidepressant medication, psychotherapy or a combination of both. Anti-depressants are effective across the full range of severity of major depressive episodes. Currently, effective antidepressive therapy is closely related to modulation or fine-tuning of serotonergic neurotransmission. Drugs that increase the levels of serotonin in the brain are the most potent known antidepressants (such as fluoxetine, Prozac® or Fluctin®). Treatments, which have antidepressive effects in patients, too, are e.g. pharmacological antidepressants such as lithium, electro-convulsive therapy and physical exercise. Other interventions include setting up supportive network systems for vulnerable individuals, families and groups. The evidence regarding prevention of depression is less conclusive, only a few isolated studies show that interventions proposed for the prevention of depression are effective. It is important to have in mind that the existing drugs are aimed at alleviating symptoms of the disease, but not primarily to address basic pathophysiological mechanisms causative to this disease. Therefore, a new treatment is needed that specifically addresses the newly discovered causal aspects in depression.
Schizophrenia is one of the most common mental illnesses. About 1 of every 100 people (1% of the population) is affected by schizophrenia. This disorder is found throughout the world and in all races and cultures. Schizophrenia affects men and women in equal numbers, although on average, men appear to develop schizophrenia earlier than women. Generally, men show the first signs of schizophrenia in their mid 20s and women show the first signs in their late 20s. Schizophrenia has a tremendous cost to society, estimated at $32.5 billion per year in the US. Schizophrenia is characterized by several of the following symptoms: delusions, hallucinations, disorganized thinking and speech, negative symptoms (social withdrawal, absence of emotion and expression, reduced energy, motivation and activity), catatonia. The main therapy for schizophrenia is based on neuropleptics, such as chlorpromazine, haloperidol, olanzapine, clozapine, thioridazine, and others. However, neuroleptic treatment often does not reduce all of the symptoms of schizophrenia. Moreover, antipsychotic treatment can have severe side effects, such as tardive dyskinesias. The etiology of schizophrenia is not clear, although there seems to be a strong genetic influence. Recently, it has become clear that schizophrenia has at least some aspects of a neurodegenerative disease. In particular, MR studies have revealed rapid cortical grey matter loss in schizophrenic patients (Thompson, et al. (2001), Proc Natl Acad Sci USA, 98, 11650-5; Cannon, et al. (2002), Proc Natl Acad Sci USA, 99, 3228-33). Therefore, treatment of schizophrenics with neuroprotective medication such as GCSF or GMCSF or other hematopoetic factors is warranted.
In humans there is a need for ways to increase cognitive capacities, and boost intelligence. “Intelligence” in modern understanding is not limited to purely logical or semantic capabilities. For example, the theory of multiple intelligences by Howard Gardner evaluates intelligence from evolutionary and anthropological perspectives and yields a broader view that includes athletic, musical, artistic, and empathetic capacities as well as the linguistic/logical abilities that are more commonly associated with intelligence and measured by IQ tests. This broader sense of intelligence also extends into the area of creativity. In addition, there is a non-pathological condition known in the human as ARML (age-related memory loss) or MCI (mild cognitive impairment) or ARCD (age-related cognitive decline) that usually commences at about age 40, and is different from early signs of Alzheimer's disease.
There is a physiological loss of nerve cells throughout adulthood, estimated to as many as 100,000 neurons a day. Throughout adulthood, there is a gradual reduction in the weight and volume of the brain. This decline is about 2% per decade. Contrary to previously held beliefs, the decline does not accelerate after the age of 50, but continues at about the same pace from early adulthood on. The accumulative effects of this are generally not noticed until older age.
While the brain does shrink in size, it does not do so uniformly. Certain structures are more prone to shrinkage. For example, the hippocampus and the frontal lobes, two structures involved in memory, often become smaller. This is partly due to a loss of neurons and partly due to the atrophy of some neurons. Many other brain structures suffer no loss in size. The slowing of mental processing may be caused by the deterioration of neurons, whether they are lost, shrink, or lose connections. This depletion of fully functioning neurons makes it necessary to recruit additional networks of neurons to manage mental tasks that would otherwise be simple or automatic. Thus, the process is slowed down.
A portion of the frontal lobe, called the prefrontal cortex, is involved in monitoring and controlling thoughts and actions. The atrophy that occurs in this brain region may account for the word finding difficulties many older adults experience. It may also account for forgetting where the car keys were put or general absentmindedness. The shrinkage of both the frontal lobe and the hippocampus are thought to be responsible for memory difficulties. Therefore, there also remains a need for improving or enhancing the cognitive ability of an individual.
In the past, neuroprotective therapies were mostly explored in neurodegenerative disorders like Parkinson's and Alzheimer's disease, and in ischaemic stroke. More recently, however, neuroprotection has been proclaimed an important goal for multiple sclerosis (MS) therapy. The basis for widening the scope of neuroprotection is evidence that neuronal and axonal injury are key features of MS lesions. Axon loss most likely determines the persistent neurological deficit in progressive MS. Recent studies pointed out that axon damage occurs early in the disease and during lesion development. Two different phases of axon degeneration were characterized, the first occurring during active myelin breakdown and the second in chronic demyelinated plaques in which the naked axon seems more susceptible to further damage. In contrast with degenerative and ischaemic central nervous system injury, however, neurodegeneration in MS appears to be caused by an inflammatory, presumably autoimmune, process. The challenge for neuroprotection in MS is therefore greater than in degenerative and ischaemic disorders, because MS requires the combination of neuroprotective therapy and effective immunomodulation. The exact mechanisms and effector molecules of axonal degeneration, however, are not yet defined, and an axon-protective therapy has not yet been established. (Bruck and Stadelmann (2003), Neurol Sci, 24 Suppl 5, S265-7) (Hohlfeld (2003), Int MS J, 10, 103-5).
One group of Neurodegenerative disorders is characterized by an expansion of trinucleotides. Those neurodegenerative trinucleotide repeat disorders are chronic and progressive characterised by selective and symmetric loss of neurons in motor, sensory, or cognitive systems. Symptoms are often ataxia, dementia or motor dysfunction. The best known trinucleotide repeat disorder is Huntingtons disease, others are Spinal and bulbar muscular atrophy (Kennedy's disease), Autosomal dominant spinocerebellar ataxia's: Type 1 SCA1, Type 2 SCA2, Type 3 (Machado-Joseph disease) SCA3/MJD, Type 6 SCA6, Type 7 SCA7, Type 8 SCA8, Friedreich's Ataxia and Dentatorubral pallidoluysian atrophy DRPLA/Haw-River syndrome. (Hardy and Gwinn-Hardy (1998), Science, 282, 1075-9) (Martin (1999), N Engl J Med, 340, 1970-80) (Schols, et al. (1997), Ann Neurol, 42, 924-32).
Huntington's disease (HD) is an autosomal dominant, inherited, neuropsychiatric disease which gives rise to progressive motor, cognitive and behavioural symptoms. The course of Huntington's is characterized by jerking uncontrollable movement of the limbs, trunk, and face (chorea); progressive loss of mental abilities; and the development of psychiatric problems. Huntington's disease progresses without remission over 10 to 25 years and usually appears in middle age (30-50 years). Juvenile HD (also called Westphal variant or akinetic-rigid HD) develops before the age of 20, progresses rapidly, and produces muscle rigidity in which the patient moves little, if at all (akinesia). It is estimated that one in every 10,000 persons—nearly 30,000 in the United States—have Huntington's disease. Juvenile Huntington's occurs in approximately 16% of all cases. Its core pathology involves degeneration of the basal ganglia, in particular, the caudate and putamen, and is caused by an unstable expansion of the trinucleotide CAG, coding for glutamine, in a single autosomal gene IT-15 on chromosome 4, coding for a mutated form of the protein, huntingtin. How the mutation of gene IT-15 alters the function of the protein is not well understood.
Treatment of Huntington's disease focuses on reducing symptoms, preventing complications, and providing support and assistance to the patient. There are several substances available today for the treatment of chorea. Other neurological symptoms, such as dystonia, can be treated, but treatment is associated with a high risk of adverse events. Psychiatric symptoms, on the other hand, are often amenable to treatment and relief of these symptoms may provide significant improvement in quality of life. (Bonelli and Hofmann (2004), Expert Opin Pharmacother, 5, 767-76). Most drugs used to treat the symptoms of HD have side effects such as fatigue, restlessness, or hyperexcitability. Cystamine (=Decarboxycystine) alleviates tremors and prolongs life in mice with the gene mutation for Huntington's disease (HD). The drug appears to work by increasing the activity of proteins that protect nerve cells, or neurons, from degeneration. The study suggests that a similar treatment may one day be useful in humans with HD and related disorders. (Karpuj, et al. (2002), Nat Med, 8, 143-9).
Glaucoma is the number one cause of preventable blindness in the United States. Glaucoma is a group of conditions where the nerve of sight (the optic nerve) is damaged, usually as a result of increased pressure within the eye, but glaucoma can also occur with normal or even below-normal eye pressure. The lamina cribrosa (LC) region of the optic nerve head (ONH) is a major site of injury in glaucomatous optic neuropathy. It is a patchy loss of vision, which is permanent, but progress of the condition can be minimised if it is detected early enough and treatment is begun. However, if left untreated, glaucoma can eventually lead to blindness. Glaucoma is one of the most common eye disorders amongst older people. Worldwide, it is estimated that about 66.8 million people have visual impairment from glaucoma, with 6.7 million suffering from blindness.
There are a variety of different types of glaucoma. The most common forms are: Primary Open-Angle Glaucoma; Normal Tension Glaucoma; Angle-Closure Glaucoma; Acute Glaucoma; Pigmentary Glaucoma; Exfoliation Syndrome or Trauma-Related Glaucoma.
Glaucoma can be treated with eyedrops, pills, laser surgery, eye operations, or a combination of methods. The whole purpose of treatment is to prevent further loss of vision. This is imperative as loss of vision due to glaucoma is irreversible. Keeping the IOP under control is the key to preventing loss of vision from glaucoma.
Peripheral neuropathy is a pain initiated or caused by a primary lesion or dysfunction of the nervous system. Many classification systems exist but typically it is divided into central (i.e. thalamic, post-stroke pain) and peripheral deafferent pain (i.e. meralgia paresthetica). Neuropathies may affect just one nerve (mononeuropathy) or several nerves (polyneuropathy). They are allodynia, hyperalgesia, and dysesthesias. Common symptoms include burning, stabbing, electric shock, or deep aching sensations. The causes of neuralgia include diabetic neuropathy, trigeminal neuralgia, complex regional pain syndrome and post-herpetic neuralgia, uremia, AIDS, or nutritional deficiencies. Other causes include mechanical pressure such as compression or entrapment, direct trauma, penetrating injuries, contusions, fracture or dislocated bones; pressure involving the superficial nerves (ulna, radial, or peroneal) which can result from prolonged use of crutches or staying in one position for too long, or from a tumor; intraneural hemorrhage; exposure to cold or radiation or, rarely, certain medicines or toxic substances; and vascular or collagen disorders such as atherosclerosis, systemic lupus erythematosus, scleroderma, sarcoidosis, rheumatoid arthritis, and polyarteritis nodosa. A common example of entrapment neuropathy is carpal tunnel syndrome, which has become more common because of the increasing use of computers. Although the causes of peripheral neuropathy are diverse, they produce common symptoms including weakness, numbness, paresthesia (abnormal sensations such as burning, tickling, pricking or tingling) and pain in the arms, hands, legs and/or feet. A large number of cases are of unknown cause.
Treating the underlying condition may relieve some cases of peripheral neuropathy. In other cases, treatment may focus on managing pain. Therapy for peripheral neuropathy differs depending on the cause. For example, therapy for peripheral neuropathy caused by diabetes involves control of the diabetes. In cases where a tumor or ruptured disc is the cause, therapy may involve surgery to remove the tumor or to repair the ruptured disc. In entrapment or compression neuropathy treatment may consist of splinting or surgical decompression of the ulnar or median nerves. Peroneal and radial compression neuropathies may require avoidance of pressure. Physical therapy and/or splints may be useful in preventing contractures. Peripheral nerves have a remarkable ability to regenerate themselves, and new treatments using nerve growth factors or gene therapy may offer even better chances for recovery in the future.
The lysosomal storage diseases are a group of about 40 different diseases, each characterised by a specific lysosomal enzyme deficiency in a variety of tissues. They occur in total in about 1 in 5,000 live births and display considerable clinical and biochemical heterogeneity. The majority are inherited as autosomal recessive conditions although two (Hunter disease and Fabry disease) are X-linked. They include Tay-Sachs disease, a gangliosidosis, and Gaucher's and Niemann-Pick's diseases, which are lipid storage disorders. Most of these diseases affect the brain and are fatal. (Brooks, et al. (2002), Proc Natl Acad Sci USA, 99, 6216-21).
There has been limited success in only treating the symptoms of these diseases. One way is to replace the enzyme to put a normal gene into the body that can make the enzyme by bone marrow or stem cell transplant or gene therapy. Bone marrow transplantation (BMT) has been successful in several LSDs and allowed long term survival with less severe symptoms. Enzyme replacement therapy (ERT) has been available for patients with Gaucher disease for over 10 years and has provided enormous benefit.
Spinal cord injury (SCI) occurs when a traumatic event results in damage to cells within the spinal cord or severs the nerve tracts that relay signals up and down the spinal cord. The most common types of SCI include contusion (bruising of the spinal cord) and compression (caused by pressure on the spinal cord). Other types of injuries include lacerations (severing or tearing of some nerve fibers, such as damage caused by a gun shot wound), and central cord syndrome (specific damage to the corticospinal tracts of the cervical region of the spinal cord). Severe SCI often causes paralysis (loss of control over voluntary movement and muscles of the body) and loss of sensation and reflex function below the point of injury, including autonomic activity such as breathing and other activities such as bowel and bladder control. Other symptoms such as pain or sensitivity to stimuli, muscle spasms, and sexual dysfunction may develop over time. SCI patients are also prone to develop secondary medical problems, such as bladder infections, lung infections, and bed sores. While recent advances in emergency care and rehabilitation allow many SCI patients to survive, methods for reducing the extent of injury and for restoring function are still limited. Immediate treatment for acute SCI includes techniques to relieve cord compression, prompt (within 8 hours of the injury) drug therapy with corticosteroids such as methylprednisolone to minimize cell damage, and stabilization of the vertebrae of the spine to prevent further injury. The types of disability associated with SCI vary greatly depending on the severity of the injury, the segment of the spinal cord at which the injury occurs, and which nerve fibers are damaged.
In view of the above, there is a need for treating neurological and/or psychiatric conditions, such as neurological diseases that relate to the enhancement of plasticity and functional recovery, or cell-death in the nervous system. In particular, there is a need for treating neurological diseases by providing neuroprotection to the neural cells involved or to induce neurogenesis to recover from neuronal loss.